Tree Problem

Our tree in the front yard is looking a little less than healthy lately.  At the beginning of the summer it started turning a kind of reddish-brown color (as did a lot of trees on our street).  I wasn't too worried about that because I thought maybe it was just a different kind of tree than I thought and it naturally had reddish leaves.  But now a lot of the leaves have turned black around the edges!  I'm not sure if it needs more water, but we water it almost every day.....could it be because we have rock around the bottom and it's not getting enough oxygen to the roots or something???? If anyone has any suggestions I'm open to them!  We also have those tree spikes in the ground by it so it gets nutrients.....I just don't know. I hope it pulls through!